1. Field of the Invention
The present invention relates to the field of ground joint couplings for hoses for transporting steam, high or low-pressure air, water, liquid petroleum gas, fluid petroleum products, chemicals, potable fluids, or almost any other type of fluid or gas, and more particularly concerns ground joint couplings having a polymeric seat for sealing the ground joint coupling.
2. Description of the Prior Art
Conventional ground joint couplings for hoses comprise a stem and a spud held together by a nut. Sealing the coupling between the stem and the spud is accomplished by pressing a ground joint head formed in one end portion of the stem into a copper seat positioned in a recess in an end portion of a spud.
With conventional ground joint couplings, the process of making the copper seat and the process of providing a spud having the copper seat are time consuming and wasteful.
A copper seat is made by cutting off or rolling off from a copper pipe a portion of appropriate length for the seat. This portion of copper pipe in the form of a ring is then annealed. The annealed ring is then manually placed in a recess formed in the end portion of the spud, where it is machined to the appropriate drawing dimensions. The spud, with the copper seat in place, is then zinc plated. The zinc plating is then polished off the copper seat.
Errors in these processes result in the copper seat and/or the spud with copper seat being scrapped or reworked.
Also, with the copper seat coupling, sealing requires impact tightening (e.g., tightening the coupling by impacting the lug of the nut manually with a hammer or the like). Accordingly, the copper seat is not field replaceable because the copper seat is very difficult to separate from the recess of the spud after impact tightening.
with the copper seat coupling, if the copper seat is dented during processing or handling, it is difficult to seal the coupling even after impact tightening.